Vehicle light assembly comprising flexible lighting strip

ABSTRACT

A vehicle light assembly comprising: a flexible lighting strip with a multitude of light-emitting diodes that are bent around at least two linear independent axes; an optically passive lighting strip terminator that is coupled to an end surface of the flexible lighting strip and is arranged such that light emitted by the light emitting diodes is at least partly recycled; a light guiding structure comprising a light receiving surface that receives light emitted by the flexible lighting strip and the lighting strip terminator and surface defines a bending of the flexible lighting strip and a primary light emission surface that emits at least a part of the light received via the light receiving surface; a coupling structure that mechanically couples the flexible lighting strip and the lighting strip terminator to the light receiving surface. The vehicle light assembly can further be comprised in a front or rear vehicle light.

FIELD OF THE INVENTION

The invention relates to a vehicle light assembly comprising a flexiblelighting strip. The invention further shows an electrical interfacewhich can be used to electrically connect a flexible lighting stripwithin such a vehicle light assembly. The invention further showsconnectors which can be used to optically and/or mechanically connecttwo or more flexible lighting strips. The invention further shows alighting strip terminator which can be used to finalize a flexiblelighting strip. The invention finally relates to a vehicle rear light orvehicle front light comprising such a vehicle light assembly.

BACKGROUND OF THE INVENTION

Recent vehicle rear lights or front lights comprise light-emittingdiodes (LED). The small size of LEDs enables customization of lightpatterns which can be provided by means of such vehicle light sources.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a vehicle lightassembly comprising one or more flexible lighting strip(s) comprising amultitude of LEDs. The vehicle light assembly aims to improveflexibility with respect to definition of light patterns which can beprovided by means of a vehicle rear light or front light. Signaling ofvehicle rear lights or front lights may be improved by means of thevehicle light assembly. The vehicle light assembly further aims toprovide a simple building set or kit to provide a customized vehiclefront or rear light.

The invention is defined by the independent claims. The dependent claimsdefine advantageous embodiments.

According to a first aspect a vehicle light assembly is provided. Thevehicle light assembly comprises:

-   -   a flexible lighting strip comprising a multitude of        light-emitting diodes (LEDs), wherein the flexible lighting        strip is arranged to be bended around at least two, more        preferred three linear independent axes;    -   a lighting strip terminator, wherein the lighting strip        terminator is coupled to an end surface of the flexible lighting        strip, wherein the lighting strip terminator is arranged such        that light emitted by the light emitting diodes leaving the        flexible lighting strip via the end surface of the flexible        lighting strip is at least partly recycled;    -   a light guiding structure comprising a light receiving surface        and a primary light emission surface, wherein the light        receiving surface is arranged to receive light emitted by the        flexible lighting strip and the lighting strip terminator,        wherein the primary light emission surface is arranged to emit        at least a part of the light received via the light receiving        surface, and wherein the light receiving surface is arranged to        define a bending of the flexible lighting strip;    -   a coupling structure, wherein the coupling structure is arranged        to mechanically couple the flexible lighting strip and the        lighting strip terminator to the light receiving surface in        accordance with the bending defined by the light receiving        surface.

The flexible lighting strip is preferably sealed against environment andemits light via one side: the light output surface of the flexiblelighting strip. Especially the other part of the perimeter of theflexible lighting strip may provide a mechanical interface to mount theflexible lighting strip within in the vehicle light assembly. Theflexible lighting strip is preferably adapted such that a homogeneouslight emission is provided. Homogeneous light emission means that it isessentially not possible to identify emission of a single LED comprisedby the flexible lighting strip. Luminance of the flexible lighting stripis essential constant across the whole light output surface. Theflexible lighting strip is arranged as a linear extended and bendablelight source which preferably provides a Lambertian directional lightemission profile with a moderately collimated output (e.g. 60° to 80°Full Width at Half Maximum—FWHM). The light output surface preferablyextends across the complete length of the flexible lighting strip suchthat there are no dark ends. The flexible lighting strip preferablyemits white or colored light in the range between 10 lm/m and 200 lm/m.The flexible lighting strip is preferably bendable around all threedimensions for mounting in the vehicle light assembly. The flexiblelighting strip is therefore also bendable around the axis of lightemission defined by a normal of the light output surface. Prior art flexboards are only bendable around 1 axis at any location. The length ofthe flexible lighting strip may be between 10 cm and 200 cm. A width ofthe flexible lighting strip perpendicular to the normal of the lightoutput surface and the linear extension of the straight flexiblelighting strip (no bending) is preferably less than 10 mm, the lightoutput surface has a width of preferably less than 4 mm.

Conventional vehicle light sources are arranged such that the lightsource determines the corresponding optic in order to provide a definedlight pattern. The flexible lighting strip is in contrast to thisconventional approach adapted such that the coupling structure, thelight receiving surface and/or the at least one primary light emissionsurface defines a light emission pattern which can be provided by meansof the vehicle light assembly. A local curvature of the couplingstructure and/or the light receiving surface may determine a localcurvature or bending of the lighting strip.

The vehicle light assembly comprises one or more lighting stripterminators. The lighting strip terminator may be coupled to a lateralend surface of the flexible lighting strip (perpendicular to thelongitudinal extension and the light output surface of the flexiblelighting strip). The lighting strip terminator is arranged such thatlight emitted by the light emitting diodes leaving the flexible lightingstrip via the end surface is at least partly recycled.

The lighting strip terminator comprises a coupling interface at the endsurface which may be arranged in the same way as described below withrespect to the connector and the flexible lighting strip. The couplinginterface of the lighting strip terminator may be coupled to acorresponding coupling interface of the flexible lighting strip in thesame way as described below with respect to the connector such thatessentially all light impinging on the end surface enters the lightingstrip terminator. The construction of the lighting strip terminator maybe very similar to the construction of the connector. The lighting stripterminator may comprise a carrier and the layer as described below. Thelighting strip terminator may optionally be as flexible as theconnector. Light mixing and/or scattering of light entering the lightingstrip terminator via the optical interface is preferably arranged suchthat the luminance of a light output surface of the light stripterminator is the same as the luminance of the flexible lighting stripoptically coupled to the lighting strip terminator. Reflection and/orscattering in the lighting strip terminator may therefore be adaptedaccordingly. Length of the light output surface of the lighting stripterminator from the coupling interface may therefore be the same or(depending on absorption and other optical losses) or less than thedistance between two LEDs in the flexible lighting strip minus distancebetween the last LED in the flexible lighting strip to the couplinginterface. The lighting strip terminator may especially be arranged toincrease the length of the flexible lighting strip by 0.5 cm or 1 cm.

The lighting strip terminator comprises a light output surface, whereinthe lighting strip terminator is arranged to receive at least a part ofthe light leaving the flexible lighting strip via the lateral endsurface (coupling interface of the flexible lighting strip). Thelighting strip terminator is arranged to emit at least a part of thereceived light via the light output surface.

The lighting strip terminator may be an integrated part of the flexiblelighting strip. The lighting strip terminator may, for example, be anextension of the flexible lighting strip without LED. The sequence ofLEDs ends and there is no further LED in comparison to the step width inwhich the LEDs are arranged in the flexible lighting strip to activelyilluminate the lighting strip terminator.

The lighting strip terminator may alternatively be a separate structurewhich comprises a coupling interface for optically coupling the lightingstrip terminator to the end surface of the flexible lighting strip.

The flexible lighting strip is arranged such that a luminance of thelight output surface of the flexible light strip is essentiallyconstant. The lighting strip terminator is arranged such that aluminance of the light output area deviates from the luminance of thelight output surface of the flexible lighting strip by less than 30%preferably less than 15% and most preferably less than 10%.

Experiments have shown that the flexible lighting strip can be arrangedsuch that the flux emitted from the side or lateral end surfaces of theflexible lighting strips is essentially constant across the lateral endsurface and essentially independent of the length of the flexiblelighting strip. It is therefore possible by means of the lighting stripterminator to extend the light emitting length of a given flexiblelighting strip in discrete steps (e.g. 0.5 cm or 1 cm) without providingan electrical connection to the passive lighting strip terminator. Thelighting strip terminator enables an increased length of homogeneouslight emission. The lighting strip terminator is optically passive inthe sense that the step width of the LEDs comprised by the flexiblelighting strip is not continued in the lighting strip terminator.

The lighting strip terminator may comprise a base and side wallsbuilding a channel as described in more detail in context with theflexible lighting strip and the connector described below. The lightingstrip terminator may further comprise a layer for distributing lightarranged in the channel as described in more detail in context with theflexible lighting strip and the connector described below. The innersurfaces of the channel may be reflective, especially diffuselyreflective. A cross-section of the channel of the lighting stripterminator may be reduced with increasing distance to the end of thecoupling interface of flexible lighting strip such that a deviation ofthe luminance of the light output area with respect to the luminance ofthe light output surface of the flexible lighting strip is reduced. Aprofile of the cross-section of the channel may be adapted to the lengthand the flux received via the lateral end surface of the flexiblelighting strip such that an essentially homogeneous luminance of thelight output area starting from a position next to the light output areaof the flexible lighting strip until the end of the light output surfaceof the lighting strip terminator is enabled. The luminance homogeneitythat is measured deviates from the homogeneity that is observed by thehuman eye. Typically, measurements record the luminance with detectorsthat have a linear response (e.g. CCD cameras). However, the human eyehas a more logarithmic response. This makes small deviations often lessvisible than we think based on the measurements. A deviation of 30% istherefore less severe when observed by the human eye.

The lighting strip terminator may, for example, comprise a wedgearranged in the channel between the side walls in order to reduce thecross-section of the channel starting from the coupling interface to theflexible lighting strip to the end of the light output surface or areaof the lighting strip terminator. The wedge is arranged such thatreflection of received light in the direction of the light outputsurface is homogenized to reduce the deviation of the luminance of thelight output surface with respect the luminance of the light outputsurface of the flexible lighting strip. The reflectivity of the surfaceof the wedge may be characterized by a gradient of rather lowreflectivity near to the coupling interface to the flexible lightingstrip and rather high reflectivity at the end of the light outputsurface of the lighting strip terminator. The gradient of thereflectivity may be adapted to the shape of the inner surface of thechannel of the lighting strip terminator. Alternatively or in addition ashape of the reflecting surface in the channel may be designed such thata uniform luminance at the light output surface may be enabled.

The lighting strip terminator may alternatively or in addition comprisescattering particles. The scattering particles are arranged such that adeviation of the luminance of the light output surface with respect tothe luminance of the light output surface of the flexible lighting stripis reduced. The scattering particles may be comprised by the layer orarranged in a scattering layer on top of the layer. The scattering layermay, for example, be a diffusor (silicone) layer. The concentration ofthe scattering particles in the channel or the scattering layer may varyin order to enable a homogeneous luminance of the light output surfaceof the lighting strip terminator. The concentration of the scatteringparticles may, for example, increase with increasing distance from thecoupling interface to the flexible lighting strip. The scattering layermay enable a uniform appearance in the off-state of the flexiblelighting strip. This may especially be relevant for the lighting stripterminator as the lighting strip terminator is built differently thanthe flexible lighting strip.

The lighting strip terminator may alternatively or in addition compriselight absorbing particles. The light absorbing particles are arrangedsuch that a deviation of the luminance of the light output surface withrespect to the luminance of the light output surface of the flexiblelighting strip is reduced. Especially in case of a short lighting stripterminator it may be that the luminance of the light output surfacewould be too high in comparison to the luminance of the light outputsurface of the flexible lighting strip. The light absorbing particlesmay therefore be used to reduce the luminance in accordance with theluminance of the light output surface of the flexible lighting strip.The light absorbing particles may be comprised by the layer or arrangedin a light absorbing layer on top of the layer. The light absorbinglayer may, for example, be a silicone layer comprising the lightabsorbing particles arranged on top of the layer. The concentration ofthe light absorbing particles in the channel or the light absorbinglayer may vary in order to enable a homogeneous luminance of the lightoutput surface of the lighting strip terminator. The concentration ofthe light absorbing particles may, for example, decrease with increasingdistance from the coupling interface to the flexible lighting strip.

The flexible lighting strip may comprise:

an elongate, flexible support;

at least one line of LEDs mounted on the flexible support; and

a carrier structure for carrying the flexible support, wherein thecarrier structure comprises:

a flexible base on which the flexible support is mounted;

flexible side walls to each side of the flexible support, defining achannel over the flexible support, the side walls providing a lightmixing function within the channel; and

a flexible layer in the channel, the top of the channel forming thelight output area or surface of the flexible lighting strip, wherein theflexible layer is adapted to increase the uniformity of the light outputand/or increase the collimation of the light output.

The flexible lighting strip provides an elongate arrangement of LEDswhich may be deformed into a desired 3D configuration. In this way, astandard component which may be mass produced may be used for multipledifferent applications, thereby reducing manufacturing costs. Theflexible layer performs an optical function.

The channel defined by the carrier structure functions as a mixingchamber over the LEDs. The channel dimensions and the material of thecarrier structure determine the way the light output from the multipleLEDs is mixed or shaped. The top of the channel defines the light outputsurface, which is thus in a strip shape. The flexible layer may betransparent, but it may additionally have a scattering function. Thescattering may be uniform or there may be different scattering intensityat different points in the volume of the layer. This scattering functionmay be used to generate a specific desired beam. Many beam variationsare then possible.

The lighting strip may be made very compact and can be shaped intoalmost any form desired by the required light emission pattern.

The carrier may be formed from a flexible white material or awhite-coated material or a mirror-coated material, so that the sidewalls mix the light within the channel by scattering of light at thechannel sides. In this way, a continuous strip of illumination may beformed. However, discrete light output points may instead be visible ifdesired. The carrier may be formed from an extruded material such assilicone. The carrier may also be selected as a thermally conductivematerial to provide a heat dissipation function.

The flexible layer may comprise an extruded component such as asilicone. This defines the light output surface, and it may perform anoptical processing function such as beam shaping or scattering. Forexample, it may comprise a scattering medium or diffractive structures.

The characteristics of the light output can be controlled by suitableselection of the materials and/or surface properties of the carrierstructure, the dimensions of the channel, and the material and opticalproperties of the flexible layer. These components and parameterstogether function to process the light output from the LEDs.

The flexible support may comprise a flexible electrical connectionstructure like a flexible printed circuit board or a lead frame. Ineither case, the support carries the LEDs and is able to be deformed toadopt a desired shape as described above.

The LEDs may each comprise a direct color emitting chip or a chip with aphosphor converter. They are, for example, formed as discrete elementsmounted on the carrier. Each LED may comprise a respective outputstructure. This may perform an optical function as well as a protectivefunction.

The flexible layer may comprise a multi-layer structure, wherein themultiple layers are formed from different materials or materials withdifferent optical coatings.

The flexible layer may comprise an exit structure at the top, whichcomprises an array of light redirecting facets (such as parallel prismsor a Fresnel structure) or an array of lenses. Alternatively, an arrayof light redirecting facets or an array of lenses may be provided withinthe flexible layer.

The flexible layer may instead or additionally comprise a patternedreflecting layer, the pattern comprising an array of openings in thelayer. This may be at the top of the channel or at a different heightwithin the channel. The flexible layer may comprise a total internalreflection lightguide structure. This may be used to average the lightoutput over area to reduce the visibility of the LEDs such that anessentially homogeneous flexible linear light source is provided.

The vehicle light assembly may comprise two, three, four or moreflexible lighting strips which may be arranged in a serial, parallel orcombined arrangement or more generally in a branched arrangement asdescribed below.

The light guiding structure or light distribution structure is arrangedto distribute light emitted by the flexible lighting strip or flexiblelighting strips. The light guiding structure may comprise a light guidecomprising at least a part of the light receiving surface and at least apart of the primary light emission surface. The light guide may, forexample, be a light blade with at least one light receiving surface andat least one primary light emission surface. The light receiving surfaceand or the primary light emission surface may comprise a coatingstructure in order to influence the light emission pattern which can beprovided by means of the vehicle light assembly. The light guide mayalternatively have any shape in order to provide a required lightpattern. The light guide may, for example, comprise one or moresecondary light emission surfaces. The secondary light emission surfaceis arranged to emit at least a part of the light received via the lightreceiving surface. The one or more primary light emission surface(s)may, for example, emit a major part of the light received via the lightreceiving surface wherein the one or more secondary light emissionsurface(s) may be arranged to emit a minor part of the light receivedvia the light receiving surface in order to provide a defined lightpattern. The primary light emission surface(s) may alternatively providea higher luminance than the secondary light emission surface(s) but theluminous flux provided by means of the primary light emission surface(s)may be smaller than the luminous flux provided by means of the secondarylight emission surface(s).

The light guiding structure may alternatively or in addition comprise areflective structure. The reflective structure comprises at least a partof the light receiving surface and at least a part of the primary lightemission surface. The respective part of the light receiving surface andthe primary light emission surface are in comparison to theconfiguration discussed above (light guide) identical. The light outputsurface of the flexible lighting strip may be arranged by means of thecoupling structure such that the reflective structure is illuminated ina defined way. Curvature or bending of the flexible lighting strip isadapted to the reflective characteristic provided by means of thereflective structure in order to provide a required or defined lightpattern. The reflective structure may comprise reflective substructures.A first reflective substructure may, for example, be a specularreflective surface. A second reflective substructure may, for example,be a diffuse reflective surface. Combination of one or more specularreflective surfaces and/or one or more diffuse reflective surfaces maybe used in order to define a required lighting pattern.

The light guiding structure may alternatively or in addition comprise ascattering structure. The scattering structure comprises at least a partof the light receiving surface and at least a part of the primary lightemission surface. The scattering structure is used to widen a lightdistribution provided by means of the flexible lighting strip. Thescattering structure may be combined with one or more light guidesand/or one or more reflective structures.

The light receiving surface may be bended around at least one,preferably at least two of the three linear independent axes (e.g. axesof a Cartesian coordinate system). Bending of the light receivingsurface of the light guide used as light guiding structure causes acorresponding bending of the flexible lighting strip because the lightoutput surface is mechanically coupled to the light receiving surface bymeans of the coupling structure. Local curvature of the light outputsurface of the flexible lighting strip is in this case mechanicallydetermined by the curvature of the light receiving surface. The lightguide may additionally arranged such that one or more secondary lightemission surface(s) is/are bended around at least two of the threelinear independent axes. Local curvature of the secondary light emissionsurface influences light outcoupling because of changing total internalreflection properties at the secondary light outcoupling surface of thelight guide. The local curvature of the secondary light emission surfacecan therefore be arranged such that a defined light pattern is providedby means of the vehicle light assembly. The one or more secondary lightemission surface may further comprise a coating structure (e.g.reflective coating) in order to influence the light pattern provided bythe vehicle light assembly. The coating structure may comprise a foil ora film coating provided on the secondary light emission surface.

Local curvature of a light receiving surface of a reflective structureor scattering structure determines local curvature of the light outputsurface of the flexible lighting strip (or local curvature of theflexible lighting strip) by the intended optical coupling in order toprovide a required light pattern.

The light guide may comprise at least one notch such that the primarylight emission surface is discontinuous (or there is according to analternative description depending on the number of notches a definednumber of primary light emission surface which appear during lightemission to be separated from each other). A notch may be, for example,a saw lane through the light guide extending from the primary lightemission surface to, for example, the light receiving surface withoutseparating the light guide (e.g. light blade). The light guide comprisesa base structure connecting finger structures extending from the basestructure wherein the finger structures are separated by the notches.One or more notches may be used to enable a discontinuous primary lightemission surface. The separated parts of the primary light emissionsurface can be twisted with respect to each other. Twisting of theseparated parts of the primary light emission surface is enabled bymeans of twisting the finger structures. Twisting may, for example beenabled by means of a transparent material which may be deformed(twisted or bended) during a heating procedure after providing sawlanes. Alternatively, molding with properly designed tools or 3-Dprinting may be used in order to manufacture such complex bended andtwisted light guides in order to provide at least one discontinuousprimary light emission surface. The notches enable a defined lightemission pattern without the need of separate lighting modules andcorresponding electrical connections.

The primary and/or secondary light emission surface may comprise a lightoutcoupling structure. The light outcoupling structure may be, forexample, a defined scratch increasing the light output. The lightoutcoupling structure may alternatively comprise volume scatteringincreasing or decreasing in combination with the local curvature of thelight guide light output via the primary and/or secondary light emissionsurface. Volume scattering may be enabled by means of scatteringparticles provided within the material of the light guide.

The coupling structure may be an integrated part of the light guidingstructure. The coupling structure may be a socket or slot comprised bythe light guiding structure by means of which the flexible lightingstrip can be fixed such that the light output surface of the flexiblelighting strip has a defined curvature in order to emit light in adefined way to the light receiving surface.

The coupling structure may alternatively be a separate structure whichcomprises a mechanical coupling surface for receiving the flexiblelighting strip and a fixing structure for fixing the coupling structuresuch that the flexible lighting strip is arranged between the mechanicalcoupling surface and the light receiving surface. The coupling structurecan in this configuration be removed from the light guiding structure.The flexible lighting strip may be placed on the mechanical couplingsurface such that the light output surface is characterized by a definedlocal curvature in order to emit light in a defined way to the lightreceiving surface. The coupling structure may alternatively or inaddition be flexible such that bending of the flexible lighting strip isdefined during the coupling process of the coupling structure to thelight guiding structure.

The vehicle light assembly may comprise at least one flexible lightingstrip. The vehicle light assembly may further comprise at least oneconnector for connecting end-surfaces of the at least one flexiblelighting strip such that a homogeneous light emission surface isprovided by the at least one flexible lighting strips and the at leastone connector. The connector may, for example, be arranged to connecttwo end surfaces of a flexible lighting strip in a circular arrangement.One end surface of the flexible lighting strip is connected to a firstcoupling interface of the connector and another second end surface ofthe flexible lighting strip is connected to a second coupling interfaceof the connector in order to provide circular vehicle light assembly.The connector may according to an alternative embodiment be a linearconnector in order to provide a linear extended arrangement of twoflexible lighting strips or an edge connector in order to connect one ortwo flexible lighting strips at a corner of the vehicle light assembly.The connector may e.g. be arranged to visually and continuously connecttwo flexible lighting strips which are arranged to be separated fromeach other. A first flexible lighting strip may, for example, bearranged on a trunk deck and the second flexible lighting strip whichcan be connected by means of the connector to the first flexiblelighting strip may be arranged on the trunk. The connector mayalternatively be arranged to connect three, four or more flexiblelighting strips such that a homogeneous light emission is provided bymeans of the three, four or more flexible lighting strips and theconnector. The connector may in this configuration be arranged toconnect the flexible lighting strips in a star like configuration. Theconnector may alternatively be arranged to connect the three, four ormore flexible lighting strips in a corner of the vehicle light assemblysimilar as the case of two flexible lighting strips.

The connector may be arranged in a similar way as the flexible lightingstrip described above. The connector may comprise:

a carrier structure comprising:

a base and side walls defining a channel, the base and/or side wallsproviding a light mixing and/or light extraction function within thechannel;

a layer in the channel, the top of the channel forming the light outputarea or surface of the connector, wherein the layer is adapted toincrease the uniformity of the light output; and

at least two coupling interfaces which are arranged to be mechanicallyand optically coupled to flexible lighting strips described above.

The connector may optionally be deformed into a desired 3Dconfiguration. The base, side walls and the layer in the channel are inthis case flexible such that the connector can be bended in at least onedimension, preferably at least two dimensions and most preferably in allthree dimensions. In this way, a standard component which may be massproduced may be used for multiple different applications, therebyreducing manufacturing costs. The layer or flexible layer arranged inthe channel performs an optical function.

The channel defined by the carrier structure functions as a mixingchamber and/or light extraction function of light emitted by an flexiblelighting strip coupled to the respective coupling interface of theconnector. The top of the channel defines the light output surface. Theshape of the light output surface depends on the coupling function ofthe connector (straight connector, edge connector, connector connectingthree, four or more flexible lighting strips). The channel dimensionsand the material of the carrier structure determine the way the lightoutput received from the at least two flexible lighting strips isdistributed and mixed such that luminance of the light output surface ofthe connector is preferably the same as luminance of the flexiblelighting strips coupled to the connector. The (flexible) layer may betransparent, but it may additionally have a scattering function. Thescattering may be uniform or there may be different scattering intensityat different points in the volume of the layer. This scattering functionmay be used to generate a specific desired beam. Distribution of, forexample, scattering particles distributed in the layer is customizeddepending on the luminance of the flexible lighting strips coupled tothe connector. Homogeneous distribution of scattering particles may bechosen if luminance of the flexible lighting strips is the same. Alength of a passive linear connector may be the same as the distancebetween two LEDs in the lighting strip—2× distance from last LED in thelighting strip to coupling interface. The length may depend on lightabsorption within the connector. Scattering particles may be distributedin an inhomogeneous way (e.g. with a gradient) if flexible lightingstrips with different luminance are connected by means of the connectorin order to provide a smooth illumination pattern by means of thevehicle light assembly. The scattering and reflective properties of thebase, the side walls and the layer may be adapted to the geometricstructure of the connector (e.g. edge connector or star like connector).

The coupling interfaces of the connector and the flexible lightingstrips are perpendicular to the respective arm of the connector (notbended) in order to avoid uncontrolled outcoupling of light at thecoupling interface. Furthermore, antireflective coatings and/or acoupling material may be arranged between the flexible lighting stripsand the connectors in order to improve optical coupling. The couplingmaterial has preferably the same or nearly the same refractive index asthe material of the layer within the flexible lighting strips and theconnector.

The connector may be made very compact and can be shaped into almost anyform desired by the required light emission pattern.

The carrier may be formed from a flexible white material or awhite-coated material or a mirror-coated material, so that the sidewalls mix the light within the channel by scattering of light at thechannel sides. In this way, a continuous strip of illumination may beformed. However, discrete light output points may instead be visible ifdesired. The carrier may be formed from an extruded material such assilicone. The carrier may also be selected as a thermally conductivematerial to provide a heat dissipation function.

The layer may be a flexible layer which may comprise an extrudedcomponent such as a silicone. This defines the light output surface, andit may perform an optical processing function such as beam shaping orscattering. For example, it may comprise a scattering medium ordiffractive structures.

The characteristics of the light output can be controlled by suitableselection of the materials and/or surface properties of the carrierstructure, the dimensions of the channel, and the material and opticalproperties of the flexible layer.

The flexible layer may comprise a multi-layer structure, wherein themultiple layers are formed from different materials or materials withdifferent optical coatings.

The flexible layer may comprise an exit structure at the top, whichcomprises an array of light redirecting facets (such as parallel prismsor a Fresnel structure) or an array of lenses. Alternatively, an arrayof light redirecting facets or an array of lenses may be provided withinthe flexible layer. The latter may be enabled by means of sufficientcontrast in refractive index between the light directing facets and theupstream light transmitting material (matrix material of the transparentlayer).

The flexible layer may instead or additionally comprise a patternedreflecting layer, the pattern comprising an array of openings in thelayer. This may be at the top of the channel or at a different heightwithin the channel. The flexible layer may comprise a total internalreflection lightguide structure. This may be used to average the lightoutput over area such that an essentially homogeneous connector isprovided.

The connector may alternatively comprise a channel (base and side walls)made of a rigid material. The layer may in this case comprise a rigidmaterial (e.g. transparent plastic) or a flexible material as describedabove.

The carrier may comprise electrically conductive structures which arearranged to electrically connect two, three or more flexible lightingstrips via the coupling interface. The coupling interface is in thiscase also used for electrically coupling the flexible lighting strips.The electrically conductive structures like, for example, wires enablepower supply of more than one flexible lighting strip by means of oneelectrical interface.

The light guiding structure which is combined with the flexible lightingstrips and the connector or connectors may comprise two or more separateparts or may be one light guiding structure.

There may be one coupling structure for coupling e.g. a combination oftwo light guides and a connector to the light guiding structure.Alternatively, there may be, for example two coupling structures. Two ormore coupling structures may optionally be mechanically coupled by meansof a mechanical interconnect.

The lighting strip terminator may alternatively be arranged such that nolight is emitted by means of the lighting strip terminator. The lightingstrip terminator may comprise a preferably diffusely reflective surfacewhich is arranged at the coupling interface of the light stripterminator. The reflective surface is arranged such that luminance ofthe flexible lighting strip terminated by means of the lighting stripterminator is homogeneous at the end of the flexible lighting stripbeing coupled to the lighting strip terminator. The distance between theend of the flexible lighting strip and the center of the next LED of theflexible lighting strip is in this case preferably half the distancebetween two LEDs in the lighting strip. The lighting strip terminatormay be arranged to act as a mechanical support for mounting the vehiclelight assembly to, for example, a vehicle light source.

The lighting strip terminator may be permanently coupled to the flexiblelighting strip or may be detachably coupled to the flexible lightingstrip (trunk and trunk deck as described above).

The vehicle light assembly may comprise an electrical interface. Theelectrical interface is arranged to couple the vehicle light assembly toan external power supply.

Electrical connection pins may be soldered to a flexible electricalconnection structure (e.g. electrical lead frame or flexible board) ofthe flexible lighting strips. The connection pins and the flexibleelectrical connection structure may be overmolded in a subsequentprocessing step. The overmold may optionally act as body of theelectrical interface (plug). Alternatively, the body may be added in asubsequent step to the overmold e.g. before or after providing the, forexample, flexible silicone layer of the flexible lighting strip.

The flexible lighting strips may alternatively be arranged such that anelectrical interface can be added at least at defined positions of theflexible lighting strip after assembly of the vehicle light assembly. Anelectrical interface may, for example, comprise pins which are arrangedto penetrate the base of the flexible lighting strip in order toelectrically contact the flexible electrical connection structure of theflexible lighting strip.

A vehicle rear light or vehicle front light may comprise the vehiclelight assembly in accordance with any embodiment described above.

The vehicle light assembly may, for example, be used in daytime runninglight (DRL), tail light, stop light or turn light.

It shall be understood that a preferred embodiment of the invention canalso be any combination of the dependent claims with the respectiveindependent claim.

Further advantageous embodiments are defined below.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the invention will be apparent from andelucidated with reference to the embodiments described hereinafter.

The invention will now be described, by way of example, based onembodiments with reference to the accompanying drawings.

In the drawings:

FIG. 1 shows a principal sketch of a first embodiment of a vehicle lightassembly

FIG. 2 shows a principal sketch of a second embodiment of the vehiclelight assembly

FIG. 3 shows a principal sketch of an embodiment of a separate couplingstructure

FIG. 4 shows a principal sketch of a first embodiment of a light guidingstructure

FIG. 5 shows a principal sketch of a second embodiment of a lightguiding structure

FIG. 6 shows a principal sketch of a third embodiment of the vehiclelight assembly

FIG. 7 shows a principal sketch of a fourth embodiment of the vehiclelight assembly

FIG. 8 shows a principal sketch of a fifth embodiment of the vehiclelight assembly

FIG. 9 shows a flexible lighting strip in perspective view

FIG. 10 shows the lighting strip of FIG. 1 in cross section

FIG. 11 shows a first set of different possible designs for the flexiblelayer used in the design of FIGS. 9 and 10

FIG. 12 shows a second set of different possible designs for theflexible layer used in the design of FIGS. 9 and 10

FIG. 13 shows a principal sketch of a cross-section a first embodimentof a connector

FIG. 14 shows a principal sketch of a perspective view of the firstembodiment of a connector

FIG. 15 shows a principal sketch of a second embodiment of a connector

FIG. 16 shows a principal sketch of a third embodiment of a connector

FIG. 17 shows a principal sketch of a first embodiment of a lightingstrip terminator

FIG. 18 shows a principal sketch of an arrangement of two lighting stripterminators

FIG. 19 shows a principal sketch of a second embodiment of a lightingstrip terminator

FIG. 20 shows a principal sketch of a first embodiment of an electricalinterface

FIG. 21 shows a principal sketch of a second embodiment of theelectrical interface

FIG. 22 shows a principal sketch of a third embodiment of the electricalinterface

In the Figures, like numbers refer to like objects throughout. Objectsin the Figs. are not necessarily drawn to scale.

DETAILED DESCRIPTION OF EMBODIMENTS

Various embodiments of the invention will now be described by means ofthe Figures.

FIG. 1 shows a principal sketch of a first embodiment of a vehicle lightassembly 400. The vehicle light assembly 400 comprises a light guidingstructure 200 which is in this case a light guide. The light guidecomprises a slot in which the flexible light strip 100 is mounted. Theflexible lighting strip 100 is fixed by means of coupling structure 300.A base of the flexible lighting strip 100 is placed on a mechanicalcoupling surface 302 of the coupling structure 300. Flexible tooth likefixing structures 304 of the coupling structure 300 fix the couplingstructure 300 to the light guide by embracing corresponding bulges ofthe light guide. The flexible lighting strip 100 is arranged between thecoupling structure 300 and the light guide such that the light emittedby the flexible lighting strip 100 is received by a light receivingsurface 202 of the light guide.

FIG. 2 shows a principal sketch of a second embodiment of the vehiclelight assembly 400. The basic configuration is similar as shown in FIG.1 discussed above. The flexible lighting strip 100 is pressed in thecorresponding slot of the light guide which is bended. Flexibility ofthe flexible lighting strip 100 is such that the flexible lighting stripis in this case mainly bended around an axis which is normal to thelight receiving surface 202 (or to the light output surface of theflexible light guide 100 as described with respect to FIG. 10). Theflexible coupling structure again enables reliable fixing of theflexible lighting strip 100. The light guiding structure 200 or thelight guide comprises a primary emission surface 204 at a narrow side ofthe light guide and a secondary emission surface 208 at the wide side ofthe light guide (in this embodiment perpendicular to the primaryemission surface 204). The light guide comprises scattering particleswhich are arranged to support light extraction via the secondaryemission surface 208.

FIG. 3 shows a principal sketch of an embodiment of a separate couplingstructure 300 similar as the coupling structures 300 shown in FIGS. 1and 2. The coupling structure 300 comprises in this case a flexibleplastic material which returns in its initial position as soon as thereis no force forcing bending of the coupling structure 300. The couplingstructure may be forced to bend by a curvature of a light guidingstructure 200 as described with respect to FIG. 2. The couplingstructure 300 may alternatively comprise a material which keeps theshape after being bended. The coupling structure 300 comprises in thisembodiment clamp like fixing structures 304 with a clamping base 308.The clamping bases are connected by hinge structure 306 supportingflexibility of the coupling structure 300. A mechanical coupling surface302 (e.g. for receiving the flexible lighting strip 100) is arranged ina channel formed by the clamps of the fixing structures 304.

FIG. 4 shows a cross-section of a first embodiment of a light guidewhich may be used as light guiding structure 200. The light guide isshaped like a blade similar as shown in FIG. 1 with a primary emissionsurface 204 at a narrow side of the blade opposite to a light receivingsurface 202. The light guide or light blade further comprises couplingdents 210 which are arranged to receive, for example, the clamp likefixing structure 304 as described with respect to FIG. 3 in order to fixone or more flexible lighting strip 100 between the mechanical couplingsurface 302 and the light receiving surface 202. The coupling dents 210should be made as small as possible to prevent too much light loss dueto frustrated total internal reflection (TIR).

FIG. 5 shows a principal sketch of a second embodiment of a light guidewhich may be used as light guiding structure 200. The light guide isshaped like a blade similar as discussed with respect to FIG. 4. Thelight guide further comprises secondary light emission surfaces 206 and208 which are the wide sides of the light guide as discussed above withrespect to FIG. 2. The secondary emission surface 206 further comprisesa light outcoupling structure 206 a which is a scratch in the surface ofthe secondary emission surface 206 supporting outcoupling of lightreceived via the light receiving surface 202. The light guidingstructure 200 further comprises a socket 203 which is arranged ascoupling structure 300. The socket 203 is arranged to receive a flexiblelighting strip 100 and to fix the flexible lighting strip 100. The lightguiding structure 200 does therefore not need a separate couplingstructure as discussed with respect to FIG. 1, 2 or 3. The bulk materialof the light guide may alternatively or in addition include volumescatterers to tailor light outcoupling.

FIG. 6 shows a principal sketch of a third embodiment of the vehiclelight assembly 400. The vehicle light assembly 400 comprises fourflexible lighting strips which are not visible in FIG. 6. A first and asecond flexible lighting strip are coupled by means of the connector 500(see discussion above and below) around a corner and emit light to alight receiving surface of a first light guiding structure. The firstlight guiding structure is in this case a light guide with a firstprimary emission surface 204A and two first secondary emission surfaces206A, and 208A which are arranged essentially opposite to each other.The first and the second flexible lighting strip and the connector arecoupled to the first light guiding structure by means of a firstcoupling structure 300A which extends around a corner of the first lightguide. A second light guiding structure is coupled to a third flexiblelighting strip by means of a second coupling structure 300B which isfixed to first coupling structure 300A by mean of a mechanicalinterconnect (not shown—the first and the second light guiding structuremay alternatively be one light guide manufactured by molding in order tosupport mechanical stability of the vehicle light assembly). The secondcoupling structure 300B fixes the third light guiding structure to thesecond light guide which comprises five notches 212 separating a secondprimary emission surface 204B in six discontinuous parts. The sixthdiscontinuous parts are surfaces of a fingerlike structures extendingfrom a base of the second light guide which is coupled by means of thesecond coupling structure 300B to the third flexible lighting strip.These fingerlike structures are slightly twisted with respect to eachother such that the parts of the second primary emission surface 204Bare arranged in a scaled or fan arrangement. The second light guidecomprises second secondary emission surfaces 206B, 208B which arediscontinuous in the direction of the second primary emission surface is204B and which are connected at the base of the light guide. The first,second, third flexible lighting strip and the first and the second lightguide are arranged to build a taillight with brake light functionality.The first, second and third flexible lighting strip as well as the firstand the second light guide are bended in all three dimensions such thatthe first and the second primary emission surfaces 204A, 204B as well asthe first and the second secondary emission surface is 206A, 206B, 208A,208B are visible for a driver of a car behind a car comprising thevehicle light assembly 400. The taillight essentially encloses aflashing light which comprises a fourth flexible lighting strip (notshown), a third coupling structure (not shown) and a light guidingstructure which is a light guide with a third primary emission surface204C and secondary emission surfaces 206C, 208C enclosing an angle ofmore than 90° with the third primary emission surface 204C. The lightguides are arranged such that luminance of the primary emission surfaces204A, 204B, 204C is higher than luminance of the secondary emissionsurfaces 206A, 206B, 246C, 208A, 208B, 208C. Especially the secondaryemission surfaces 206A, 206B, 208A, 208B of the taillight provide a hazelike appearance. The vehicle lighting assembly 400 may further comprisemechanical support structures in order to provide a reliable stabilityof the vehicle light assembly 400. The mechanical support structures maybe integrated parts of the light guides. The combination of the flexiblelighting strips, coupling structures and light guiding structuresenables complex vehicle lighting assemblies.

FIG. 7 shows a principal sketch of a cross-section of a fourthembodiment of the vehicle light assembly 400. The light guidingstructure 200 comprises in this case a reflective structure with a lightreceiving surface 202 which is at the same time diffusely reflective inorder to reflect light received from a flexible lighting strip 100. Thelight receiving surface 202 coincides in this case at least partly withprimary emission surface 204. The flexible lighting strip 100 ismechanically coupled to the light guiding structure 200 by means of acoupling structure 300 which comprises a slot with a mechanical couplingsurface 302 and a fixing structure 304. The shape of the slot and theshape of the mechanical coupling surface 302 defines the shape andespecially bending of the flexible lighting strip 100 which is notvisible in the two-dimensional drawing. The fixing structure 304 fixesthe flexible lighting strip 100 in the slot such that the shape of theflexible lighting strip 100 defines together with the illuminationcharacteristic of the flexible lighting strip 100 illumination of thelight receiving surface 202. The reflective surface may optionallycomprise one or more areas which are not reflective. Light received atnot reflective areas of the light receiving surface 202 may entertransparent carrier material which may be used to build the lightguiding structure 200. Light entering the transparent carrier materialmay leave the transparent carrier material at defined surface sections(primary or secondary emission surfaces which are not shown) of thelight guiding structure 200. The light guiding structure 200 may in thiscase be a combination of a reflective structure and a light guide.

FIG. 8 shows a principal sketch of a cross-section of a fifth embodimentof the vehicle light assembly 400. The light guiding structure 200comprises in this case a scattering structure with a scattering elementat the primary emission surface 204. The light guiding structure 200comprises a transparent material such that the light received via alight receiving surface 202 can reach the scattering element. A flexiblelighting strip 100 is mechanically coupled to the light guidingstructure 200 by means of a coupling structure 300 which comprises aslot with a mechanical coupling surface 302 and a fixing structure 304.The shape of the slot and the shape of the mechanical coupling surface302 define shape and especially bending of the flexible lighting strip100 which is not visible in the two-dimensional drawing. A lightemitting surface of the flexible lighting strip 100 is in thisembodiment in contact with the mechanical coupling surface 302. Themechanical coupling surface 302 thus comprises the light receivingsurface 202 of the light guiding structure 200. The fixing structure 304fixes the flexible lighting strip 100 in the slot such that the shape ofthe flexible lighting strip 100 defines together with the illuminationcharacteristic of the flexible lighting strip 100 illumination of thelight receiving surface 202 and the scattering element at the primaryemission surface 204. It is thus not necessary that the light receivingsurface 202 touches the flexible lighting strip 100. There may, forexample, be an air gap between the light receiving surface 202 and thelight emitting surface of the flexible lighting strip 100. Fixingstructure 304 and mechanical coupling structure 302 may, for example, insuch a case be the same.

FIGS. 9, 10, 11 and 12 show a flexible elongate lighting strip having atleast one line of LEDs mounted on a flexible support and carried by acarrier structure 14. The carrier structure 14 provides light mixingwithin a channel over the line of LEDs and a flexible layer is providedin the channel for further light processing.

FIG. 9 shows a flexible lighting strip 100. A line of LEDs 10 is mountedon an elongate, flexible support 12. The flexible support 12 issupported by the carrier structure 14 having a flexible base 16 on whichthe flexible support 12 is mounted and flexible side walls 18 to eachside of the flexible support 12, defining a channel 20 over the base 16.

The channel may have parallel sides as shown, by they may instead taper,with a wider top opening than the base. This forms a funnel shape.

The base and side walls are preferably part of a single integratedcomponent, which itself may be extrusion molded. It may be molded aroundthe support 12, or else the carrier structure 14 may be fitted aroundthe support 12 after manufacture. Alternatively, the carrier structure14 may comprise separate side walls and base which are assembledtogether.

The flexible support 12 provides the electrical connections to the LEDs10 and also provides heat removal.

The LEDs 10 emit light into the channel 20, and in some examples thesurfaces of the side walls 18 provide light mixing so that a moreuniform strip of illumination is defined. The height of the channeltogether with the reflection characteristics of the side walls define abeam shaping function, whereby the light output intensity is greater inthe normal direction (perpendicular to the support 12).

A flexible layer 22 is provided in the channel. This layer performs anadditional light processing function. This function is to make the lightoutput more uniform, so that the spot-like appearance of the LEDs ismade less visible, and/or to increase the collimation and therebyprovide directional control.

All of the components (apart from the LEDs themselves) are flexible sothat the complete strip may be deformed into almost any desired 3Dconfiguration. It may be bent into an arc on a flat plane (parallel tothe support 12) or it may be deformed into an arc out of plane. Thelighting strip may be mass produced as a small range of designs (forexample of different dimensions and materials), and each design may thenbe suitable for a large range of end applications.

The top of the channel, which may be defined by the top of the flexiblelayer 22, defines the light output surface, which is in a strip shape.

The optical function of the layer 22 may be implemented by a scatteringarrangement. The scattering may be uniform along the strip or there maybe different scattering intensities at different points in the volume ofthe layer, for example by having a variation in the volume density ofscattering particles. The different scattering intensities may varyperiodically to match the spacing between the LEDs. The scatteringintensity may also vary in the normal direction. The flexible layer thusmay be used to provide shaping of the light output from the LEDs andhomogenization of the light.

The flexible layer also provides protection to the electrical trackscarried by the flexible support 12.

The scattering function may be used to generate a specific desired beam.Many beam variations are possible by suitable selection of the layer 22,even for a design which remains identical in all other respects. In thisway, only one component is varied to achieve a wide range of possibledesigns. A number of specific examples of design for the flexible layerare presented below.

FIG. 10 shows a cross section perpendicular the length direction. Itshows that the LED comprises an LED chip 24 and an optional outputstructure 26. The LED chip 24 may be a direct color emitting chip (i.e.the output of the chip is a desired color to be emitted from thelighting strip). Alternatively, the LED chip may emit one color and aphosphor converter may be provided for changing the output color. Forexample, the LED may be a blue chip, and a yellow emitting phosphor isused to create a white light output.

This phosphor converter may be part of the chip which is mounted on theflexible support 12, or it may be defined by the output structure 26.

The output structure may instead or additionally provide a beam shapingfunction, and be formed as a refractive lens.

In all cases, the output structure 26 provides protection to the chips.

By way of example, the overall product (the outer dimensions of thecarrier structure 14) may be a width 8 mm and a height 5 mm. The channelmay then have dimensions of 3 mm×3 mm.

In general, the lighting strip may have a width less than 20 mm, morepreferably less than 10 mm, and a height less than 12 mm more preferablyless than 8 mm. The strip can have any length, for example tens ofcentimeters.

There may typically be tens to hundreds of LEDs along the line. They mayfor example be spaced with a pitch of between 2 mm and 50 mm, forexample between 2 mm and 30 mm, for example between 5 mm and 20 mm.

Some examples of the materials and designs that may be used to form thedifferent components will now be discussed.

The flexible support 12 may comprise a flexible printed circuit board ora flexible electrical connection structure (e.g. lead frame). A flexibleprinted circuit board may for example be made of polyimide with coppertracks, although many other flexible carrier materials may be used. Aflexible electrical connection structure may be formed of a sheet metal,such as Cu, Al, Zn, Fe or alloys.

In either case, the support carries the LEDs and electrical tracks andis able to be deformed to adopt a desired shape. The flexible support 12may be carried directly over the base 16 of the carrier structure 14, orthere may be additional layers of material, for example for heatspreading.

As mentioned above, the LED may include a wavelength converting layer.This may be formed as part of the LED itself so that the discrete LED tobe mounted on the flexible support 12 incorporates a phosphor layer. Itmay instead be a separate component mounted over the LED, for example arigid plastic capsule which contains the phosphor converter. The LEDpackage may also include electronic components such as basic componentslike resistors, or more complicated components such as sensors orintegrated circuits.

The output structure 26 may comprise a silicone glob, or a molded partformed from rigid plastic. It may instead by formed by a dam and fillprocess. The output structure may comprise the phosphor as explainedabove, or it may be translucent (and just serve as a protection layer),or it may provide an optical beam shaping function.

The carrier structure 14 may be formed from a flexible white material ora white-coated material or a mirror-coated material, so that the sidewalls mix the light within the channel by scattering of light at thechannel sides. In this way, a continuous strip of illumination may beformed. However, discrete light output points may instead be visible ifdesired. The carrier structure 14 may be formed from extruded silicone,although other bendable materials are also possible. The carrierstructure 14 may also be selected as a thermally conductive material toprovide a heat dissipation function.

Note that in some examples light may not reach the side walls because oftotal internal reflection at the sides of the flexible layer which iswithin the channel. For example, there may be an air gap between thesides of the flexible layer, and total internal reflection may then takeplace at the layer-air interface. In this case, the carrier 14 does notneed reflecting side walls.

The flexible layer 22 may comprise an extruded component such assilicone. In this case, it may be fitted mechanically into the channel.It may instead be formed in the channel, for example as a liquid whichis then cured in place.

An upper surface of the flexible layer 22 defines the light outputsurface of the flexible lighting strip 100. A (local) normal 21 to thelight output surface defines a primary direction of light emission ofthe flexible lighting strip 100. The normal 21 is essentially parallelat every point of the light output surface as long as the flexiblelighting strip 100 is not bended. The flexible lighting strip 100 canespecially be bended around the normal 21. Bending around the differentaxes may be limited by the geometry of the flexible lighting strip 100,the width and height of the flexible lighting strip 100 or the materialproperties of the different elements of the flexible lighting strip 100.

FIG. 11 shows three examples of possible design for the flexible layer.

FIG. 11(a) shows the first design in cross section across the channeland FIG. 11(b) shows the first design in cross section along thechannel.

The output structure comprises a transparent glob. There is a coating 30on the glob, for example a white paint pattern. The layer 22 is afilling which fills the channel. It has scattering particles dispersedthroughout. These may for example be applied as a dye. The top of thefilling is covered with an exit film 32 with linear prisms or a Fresnelstructure.

The white pattern on top of the transparent glob makes the light moreuniform within the channel in a first step. The glob functions as alarger secondary light source than the chip itself.

FIG. 11(c) shows the second design in cross section across the channeland FIG. 11(d) shows the second design in cross section along thechannel.

The output structure 26 again comprises a transparent glob. The layer 22again has the structure of a filling with scattering particles dispersedthroughout. The top of the filling is covered with an exit film 32 withlinear prisms or a Fresnel structure. This second design is thus thesame as the first but without the coating on the protective glob.

FIG. 11(e) shows the third design in cross section across the channeland FIG. 11(f) shows the third design in cross section along thechannel.

The output structure 26 again comprises a transparent glob. The layer 22comprises an optical processing film 34 with partial transmittance, forexample a reflector film with a hole array. An exit film 36 comprises alens array.

FIG. 12 shows four further examples of possible design for the flexiblelayer.

FIG. 12(a) shows the fourth design in cross section across the channeland FIG. 12(b) shows the fourth design in cross section along thechannel.

The output structure 26 again comprises a transparent glob. The layer 22is shaped structure which does not fill the channel in the sidewaysdirection. Instead, air gaps 40 are present at the sides and beneath.The cross section varies along the length so that a beam shapingfunction is dependent on the position along the length of the channel.This enables a more uniform light output to be created along the lengthof the channel. In particular, total internal reflections are used topass light along the layer 22 in the manner of a light guide, with thelight escaping at locations along the top of the channel which areremote from the light sources themselves.

FIG. 12(c) shows the fifth design in cross section across the channeland FIG. 12(d) shows the fifth design in cross section along thechannel.

The output structure 26 again comprises a transparent glob, but ratherthan having the form of a single lens shape, it has a double lens shapealong the length axis of the channel. This serves to make the lightoutput more uniform in the length direction. The layer 22 comprises aprismatic or Fresnel film 42, and there is a further prismatic orFresnel exit film 44. These films combine to implement a collimationfunction.

The flexible layer may thus comprise a multi-layer structure. In theexample of FIGS. 12(c) and 12(d), the multiple layers may be the samematerial but with different surface structures. They may instead beformed from different materials, or they may be formed as layer (of thesame or different materials) with different optical coatings.

FIG. 12(e) shows the sixth design in cross section across the channel.It is extruded along the channel so no cross section along the channelis shown.

The output structure 26 again comprises a transparent glob. The layer 22is shaped structure which does not fill the channel in the sidewaysdirection. Instead, air gaps 46 are present at the sides and beneath.The cross section is constant along the length. Total internalreflections are used to shape the light, for example at the top of thechannel a lens shape 48 is defined.

FIG. 12(f) shows the seventh design in cross section across the channel.It is extruded along the channel so no cross section along the channelis shown.

The output structure directs the light in a sideways direction. Thedesign includes a so-called dark hole optic, in which the outputstructure has a high reflective coating on top, shaped to reflect lightto the sides, leaving a central dark hole. The lateral light isreflected by the side walls 50 of the channel, which in this example arecurved rather than straight. These side walls thus perform a lightshaping function. There is a prismatic or Fresnel exit film 52.

It will be seen from the examples above that the layer may be clear ordiffusive, and it may be formed as a multi-layer structure. It may havescattering elements and/or it may have diffractive elements. In the caseof a multi-layer structure, the multiple layers may be formed fromdifferent materials or materials with different optical coatings. Theremay be refractive, diffusive, diffractive or reflective optical elementsincorporated into the layer. Optical films may also be incorporated intothe layer. Alternatively, the main volume of the channel may be empty,and the layer comprises only a top exit layer or a layer within thechannel.

The overall design is created to generate desired characteristics of thelight emitted from the strip. This light may be collimated or diffuse,uniform or shaped into discrete output regions.

The example above shows one line of LEDs along the strip. There mayhowever by multiple lines of LEDs. Electrical connection to the LEDs maybe made from one or both ends of the strip, or from the back, through anopening in the base 16. The electrical connection to the lighting striphas not been shown as any conventional PCB or lead frame connector maybe used.

The LED driver electronics may be external to the lighting strip or itmay be integrated within the lighting strip.

FIG. 13 shows a principal sketch of a cross section of a firstembodiment of a connector 500. The cross section shows a carrierstructure with a flexible base 16 and flexible side walls 18 building achannel as discussed with respect to the flexible lighting strip shownin FIG. 10. The channel is filled with a flexible layer 22 in order todistribute light received from flexible lighting strips via a couplinginterface (not shown). The received light is emitted via a light outputsurface of the flexible layer 22 with a main emission direction along alocal normal of the light output surface 21. The connector 500 mayoptionally comprise a carrier structure with, for example, a flexibleelectrical connection structure (not shown) in order to enableelectrical connection of two or more flexible lighting strips opticallyand mechanically coupled by means of the connector. FIG. 14 shows aprincipal sketch of a perspective view of the first embodiment of aconnector 500. The connector 500 is arranged to connect two identicalflexible lighting strips 100 in a linear arrangement by means of twocoupling interfaces 502. Length, reflectivity and scattering propertiesof the base, the side walls and the layer within the channel defined bythe base and the side walls are arranged such that luminance of a lightemission surface of the connector 500 is essentially the same thanluminance of the coupled flexible lighting strips 100. The material ofthe base and side walls may be flexible or rigid depending on theintended arrangement of the vehicle light assembly. A flexible materialmay enable to bend the two flexible lighting strips 100 optically andmechanically coupled by means of the connector 500 across the connector500.

FIG. 15 shows a principal sketch of a perspective view of a secondembodiment of a connector 500. The general configuration of theconnector 500 is the same as discussed with respect to FIG. 13. A rigidbase 16A and two rigid sidewalls 18A form a channel with a rectangularcorner. The channel may be formed by means of a aluminum profile. Thechannel is filled with a transparent rigid layer 22A which comprises twocoupling interfaces 502. The material of the transparent rigid layer 22Amay, for example, be a transparent plastic. The connector 500 enables aconnection of two flexible lighting strips 100 at an angle of 90° bycoupling the flexible lighting strips 100 to the coupling interfaces502. Other configurations of such edge connector may enable a connectionat different angles than 90° (e.g. at an acute angle or obtuse angle).Reflectivity of the rigid base 16A and the rigid side walls 18A incombination with a defined scattering within the rigid layer 22A and thelength of the arms of the edge connector are preferably arranged that ahomogeneous luminance of the combination of the flexible lighting stripsand the edge connector is enabled. The edge connector may alternativelycomprise flexible materials as discussed with respect to FIG. 13.

FIG. 16 shows a principal sketch of a third embodiment of a connector500 which is arranged to connect three flexible lighting strips 100 bymeans of corresponding coupling interfaces 502. The generalconfiguration of the connector 500 is similar as described with respectto FIG. 13. The base and side walls and optionally the transparentmaterial placed in the channel formed by the base and side walls are inthis case made of a rigid material such that the Y shape form of theconnector 500 is fixed. Length of the three arms of the connector isadapted such that light outcoupling via a light output surface of theconnector is such that luminance of the light output surface of theflexible lighting strips 100 and the connector 500 is essentially thesame. Alternatively, length and outcoupling of light entering connector500 may be arranged to provide, for example, a smooth transition betweenflexible lighting strips with different luminance. Furthermore,connector 500 may be arranged to provide a defined lighting effect (e.g.highest luminance at the crossing of the branches or arms of connector500).

FIG. 17 shows a principal sketch of a cross section of an embodiment ofa lighting strip terminator 700. The lighting strip terminator comprisesa coupling interface 702 in order to receive light (indicated by thearrows) from a flexible lighting strip 100. The lighting stripterminator 700 comprises a base, side walls and a layer for distributingthe light between the side walls similar as discussed with respect tothe connector 500 or the flexible lighting strip 100 above. Thedifference is that in this embodiment there is a wedge arranged in thechannel between the side walls such that light received from theflexible lighting strip 100 is reflected in the direction of a lightoutput surface of the lighting strip terminator 700 which is built by asurface of the layer as discussed above. The preferably diffusereflection by means of the base and the side walls is arranged such thatluminance of the light output surface of the lighting strip terminator700 is homogeneous and essentially the same as luminance of the flexiblelighting strip 100 coupled to the lighting strip terminator 700.Scattering and/or light absorbing particles may optionally be added tothe material of the layer in order to provide a defined luminance of thelight output surface of the lighting strip terminator 700. The taperedshape of the base can also be more rounded, e.g. parabolic or anotheroptimized shape in order to direct the light more forwards out of thelight output area of the lighting strip terminator 700. Essential hereis that the light can run until the end of the light strip terminator.

FIG. 18 shows a principal sketch of an arrangement of two lighting stripterminators 700. The lighting strip terminators 700 are essentiallyidentical with the lighting strip terminator 700 discussed with respectto FIG. 17. The first lighting strip terminator 700 (left side of FIG.18) and the second lighting strip terminator 700 (right side of FIG. 18)nearly touch each other (indicated by the vertical dotted line). Thelighting strip terminators 700 may be used to provide an essentiallyuniform luminance profile from left to right. Such a configuration may,for example, be used if the first, left part is built in the bodywork ofa car while the second, right part is built into the hatch of the reardoor of the car (split rear or tail lights).

FIG. 19 shows a principal sketch of a second embodiment of a lightingstrip terminator 700. The lighting strip terminator 700 is in thisembodiment made of a piece of hard plastic or aluminum. It has a flatsurface (coupling interface) that faces an end face (coupling interface)of a flexible lighting strip 100. This flat surface comprises areflector 704 which is highly specularly reflective reflecting the lightback into the flexible lighting strip 100. In this way light that wouldotherwise be lost/absorbed is injected back into the light guide of theflexible lighting strip 100 and has a second chance of being emittedfrom the light output surface. The highly reflective face of thelighting strip terminator 700 is typically made of highly polishedaluminum or coated silver foils. Also special highly reflective foilslike Alanod may be used. The distance between the end face of theflexible lighting strip 100 and the middle of the next LED is preferablyhalf of the distance between two LEDs of the flexible lighting strip 100such that the specular reflective reflector 704 has the same effect as afurther LED at the opposite side of the reflector 704 (virtually withinthe lighting strip terminator 700).

FIG. 20 shows a principal sketch of a cross-section of a firstembodiment of an electrical interface 800. The cross section shows across-section of the flexible lighting strip as discussed with respectto FIG. 10 with a flexible base 16 flexible side walls 18 and a flexiblelayer deposited in the channel formed by the base 16 and flexible sidewalls 18 as discussed above. An LED chip 24 is electrically connected bymeans of the flexible support 12 comprising the flexible electricalconnection structure. Electrical connection pins 802 are arranged toelectrically connect the conducting paths of the flexible electricalconnection structure. A body of the electrical interface 810 surroundsthe electrical connection pins 802 such that in this embodiment a femaleplug is formed. The female plug can be connected by means of acorresponding male plug such that electrical power can be provided bymeans of a wire connected to the female plug. The other end of the wirecan be provided with any suitable plug or electrical connectiontechnology which may be beneficial in the corresponding application in arear light or front light.

FIG. 21 shows a principal sketch of a second embodiment of theelectrical interface 800. The general configuration is essentially thesame as discussed with respect to FIG. 19. The electrical interface 800is arranged at one of the longitudinal end surfaces of a flexiblelighting strip. Such an electrical interface 800 may be used if one endof a flexible lighting strip is essentially invisible in a vehicle lightassembly.

FIG. 22 shows a principal sketch of a third embodiment of the electricalinterface 800. The general configuration is essentially the same asdiscussed with respect to FIG. 19. The electrical interface 800 isarranged at an intermediate position of a flexible lighting strip. Suchan electrical interface 800 may be used if both ends of a flexiblelighting strip are visible in a vehicle light assembly. The flexiblelighting strip may, for example, be coupled by means of two passiveconnectors without electrically conductive cables in the base to twoflexible lighting strips with electrical interfaces 800 as described inFIG. 20.

While the invention has been illustrated and described in detail in thedrawings and the foregoing description, such illustration anddescription are to be considered illustrative or exemplary and notrestrictive.

From reading the present disclosure, other modifications will beapparent to persons skilled in the art. Such modifications may involveother features which are already known in the art and which may be usedinstead of or in addition to features already described herein.

Variations to the disclosed embodiments can be understood and effectedby those skilled in the art, from a study of the drawings, thedisclosure and the appended claims. In the claims, the word “comprising”does not exclude other elements or steps, and the indefinite article “a”or “an” does not exclude a plurality of elements or steps. The mere factthat certain measures are recited in mutually different dependent claimsdoes not indicate that a combination of these measures cannot be used toadvantage.

Any reference signs in the claims should not be construed as limitingthe scope thereof.

LIST OF REFERENCE NUMERALS

-   10 light-emitting diode (LED)-   12 flexible support-   14 carrier structure-   16 flexible base-   16A rigid base-   18, 50 flexible side walls-   18A rigid side walls-   20 channel-   21 normal of light output surface-   22 flexible layer-   22A rigid layer-   24 LED chip-   26 output structure-   30 coating-   32 exit film-   34 optical processing film-   36 array of lenses of facets-   40, 46 air gap-   42, 44 prismatic or Fresnel exit film

048 lens shape

-   100 flexible lighting strip-   200 light guiding structure-   202 light receiving surface-   204 primary emission surface-   204A first primary emission surface-   204B second primary emission surface-   204C third primary emission surface-   206A, 208A first secondary emission surfaces-   206B, 208B second secondary emission surface-   206C, 208C third secondary emission surface-   206, 208 secondary emission surface-   206 a light outcoupling structure-   210 coupling dent-   212 notch-   300 coupling structure-   300A first coupling structure-   300B second coupling structure-   302 mechanical coupling surface-   304 fixing structure-   306 hinge structure-   308 clamping base-   400 vehicle light assembly-   500 connector-   502, 702 coupling interface-   700 lighting strip terminator-   710 reflective wedge-   722 (flexible) base-   800 electrical interface-   802 electrical connection pin-   810 body of electrical interface

1. A vehicle light assembly comprising: a flexible lighting stripcomprising a multitude of light-emitting diodes, wherein the flexiblelighting strip is arranged to be bended around at least two, morepreferred three linear independent axes; an optically passive lightingstrip terminator, wherein the lighting strip terminator is coupled to alateral end surface of the flexible lighting strip, perpendicular to thelongitudinal extension and a light output surface of the flexiblelighting strip, wherein the lighting strip terminator is arranged suchthat light emitted by the light emitting diodes leaving the flexiblelighting strip via the end surface of the flexible lighting strip is atleast partly recycled; a light guiding structure comprising a lightreceiving surface and a primary light emission surface, wherein thelight receiving surface is arranged to receive light emitted by theflexible lighting strip and the lighting strip terminator, wherein theprimary light emission surface is arranged to emit at least a part ofthe light received via the light receiving surface, and wherein thelight receiving surface is arranged to define a bending of the flexiblelighting strip; and a coupling structure, wherein the coupling structureis arranged to mechanically couple the flexible lighting strip and thelighting strip terminator to the light receiving surface in accordancewith the bending defined by the light receiving surface.
 2. The vehiclelight assembly according to claim 1, wherein the lighting stripterminator comprises a light output surface, wherein the lighting stripterminator is arranged to receive at least a part of the light leavingthe flexible lighting strip via the end surface, and wherein thelighting strip terminator is arranged to emit at least a part of thereceived light via the light output surface.
 3. The vehicle lightassembly according to claim 1, wherein the lighting strip terminator isan integrated part of the flexible lighting strip.
 4. The vehicle lightassembly according to claim 2, wherein the lighting strip terminator isa separate structure which comprises a coupling interface for opticallycoupling the lighting strip terminator to the end surface of theflexible lighting strip.
 5. The vehicle light assembly according toclaim 4, wherein the flexible lighting strip is arranged such thatluminance of the light output surface of the flexible light strip isconstant, and wherein the lighting strip terminator is arranged suchthat luminance of the light output surface of the lighting stripterminator deviates from the luminance of a light output surface of theflexible lighting strip by less than 30%, preferably less than 15% andmost preferably less than 10%.
 6. The vehicle light assembly accordingto claim 1, wherein the lighting strip terminator comprises a base andside walls building a channel, and wherein the lighting strip terminatorfurther comprises a layer for distributing light arranged in thechannel.
 7. The vehicle light assembly according to claim 6, whereininner surfaces of the channel are reflective.
 8. The vehicle lightassembly according to claim 7, wherein the inner surfaces are diffuselyreflective.
 9. The vehicle light assembly according to claim 6, whereina cross-section of the channel is reduced with increasing distance tothe flexible lighting strip such that a deviation of the luminance ofthe light output surface of the lighting strip terminator in comparisonto the luminance of the light output surface of the flexible lightingstrip is reduced.
 10. The vehicle light assembly according to claim 9,wherein the lighting strip terminator further comprises: a wedgearranged in the channel between the side walls, wherein the wedge isarranged such that reflection of received light in the direction of thelight output surface of the lighting strip terminator is homogenized toreduce the deviation of the luminance of the light output surface of thelighting strip terminator in comparison the luminance of the lightoutput surface of the flexible lighting strip.
 11. The vehicle lightassembly according to claim 6, wherein the lighting strip terminatorfurther comprises scattering particles, and wherein the scatteringparticles are arranged such that a deviation of the luminance of thelight output surface of the lighting strip terminator in comparison tothe luminance of the light output surface of the flexible lighting stripis reduced.
 12. The vehicle light assembly according to claim 11,wherein a concentration of the scattering particles increases withincreasing distance to the flexible lighting strip.
 13. The vehiclelight assembly according to claim 6, wherein the lighting stripterminator further comprises light absorbing particles, and wherein thelight absorbing particles are arranged such that a deviation of theluminance of the light output surface of the lighting strip terminatorin comparison to the luminance of the light output surface of theflexible lighting strip is reduced.
 14. A vehicle light assemblycomprising: a flexible lighting strip comprising a multitude oflight-emitting diodes, wherein the flexible lighting strip is arrangedto be bended around at least two, more preferred three linearindependent axes; an optically passive lighting strip terminator,wherein the lighting strip terminator is coupled to a lateral endsurface of the flexible lighting strip, perpendicular to thelongitudinal extension and a light output surface of the flexiblelighting strip, wherein the lighting strip terminator is arranged suchthat light emitted by the light emitting diodes leaving the flexiblelighting strip via the end surface of the flexible lighting strip is atleast partly recycled; a light guiding structure comprising a lightreceiving surface and a primary light emission surface, wherein thelight receiving surface is arranged to receive light emitted by theflexible lighting strip and the lighting strip terminator, wherein theprimary light emission surface is arranged to emit at least a part ofthe light received via the light receiving surface, and wherein thelight receiving surface is arranged to define a bending of the flexiblelighting strip; a coupling structure, wherein the coupling structure isarranged to mechanically couple the flexible lighting strip and thelighting strip terminator to the light receiving surface in accordancewith the bending defined by the light receiving surface; and anelectrical interface, wherein the electrical interface is arranged tocouple the vehicle light assembly to an external power supply.
 15. Thevehicle light assembly according to claim 1, wherein the vehicle lightassembly is used in a vehicle rear.
 16. The vehicle light assemblyaccording to claim 1, wherein the vehicle light assembly is used in avehicle front light.
 17. The vehicle light assembly according to claim13, wherein the vehicle light assembly is used in a vehicle rear light.18. The vehicle light assembly according to claim 13, wherein thevehicle light assembly is used in a vehicle front light.